The present invention relates to a diaphragm-type solenoid valve which is for use with various flow path structures by mounting the required number of solenoid valves onto a base and which is suitable for supplying and discharging special medical fluid which must not include foreign matter.
A diaphragm-type solenoid valve is conventionally known as a valve which can easily suppress inclusion of foreign matter or the like by independently forming a flow path for main fluid. However, because the diaphragm-type solenoid valve is generally formed as a single solenoid valve, it is difficult to easily connect the solenoid valve so as to obtain various flow path structures.
If the diaphragm-type valve is used for a flow path for fluid which must not include foreign matter or which is toxic, it is necessary to give sufficient consideration such that the diaphragm is not damaged due to fatigue or
The present invention has been accomplished to solve the above problems and it is basically a technical object of the invention to provide a diaphragm-type solenoid valve by which various flow path structures can be obtained by making it possible to mount valve bodies of the required number of diaphragm-type solenoid valves to a base having a proper flow path.
It is another technical object of the invention to provide a diaphragm-type solenoid valve in which a sliding portion and excessive deformation are generated nowhere in operation of a diaphragm and the diaphragm can be prevented from being damaged due to fatigue or the like.
To achieve the above objects, according to the invention, there is provided a diaphragm-type solenoid valve comprising a valve body having a first port and a second port in a mounting face to be mounted to a base, a valve seat mounted in a flow path connecting both the ports, a diaphragm for opening and closing the valve seat, a plate for sandwiching and fixing an outer peripheral portion of the diaphragm between the plate and the valve body, a driving chamber formed between the plate and the diaphragm to be separated from the flow path, and a pilot valve disposed on the plate to supply pilot fluid different from the main fluid to the driving chamber.
The diaphragm has a central main body portion for opening and closing the valve seat and an elastic support portion surrounding the main body portion, a disc is encapsulated in the main body portion, a sealing rib for coming in contact with and separating from the valve seat is provided to one face of the main body portion, and a cushion projecting portion for coming in contact with a cushion receiving portion of the plate in valve opening is formed on a back face of the main body portion.
In the diaphragm-type solenoid valve, diaphragm receiving faces in shapes patterned on a shape of the elastic support portion are formed on opposed faces of the valve body and the plate facing the elastic support portion of the diaphragm and the elastic support portion comes in contact with the diaphragm receiving faces in opening and closing of the diaphragm to thereby prevent excessive deformation of the diaphragm.
In the invention, it is preferable that the first port is in an annular shape and the second port opens at a center of the first port.
It is preferable that a pilot air supply hole and a pilot exhaust hole communicating with the pilot valve are provided to the mounting face of the valve body.
According to the invention, there is provided a diaphragm-type solenoid valve complex body formed by mounting one diaphragm-type solenoid valve onto a base having a supply port and an output port for main fluid and connecting each of the first and second ports to one of the supply port and the output port so as to have a function of a two-port valve by the solenoid valve and the base.
There is provided a diaphragm-type solenoid valve complex body formed by mounting a plurality of diaphragm-type solenoid valves onto a base having a supply port, at least one output port, and a discharge port for main fluid and connecting the supply port, the output port, and the discharge port to first and second ports of the respective solenoid valves by a connecting path in the base so as to have a function of a three-port valve by the plurality of solenoid valves and the base.
According to a concrete embodiment of the three-port valve, the base has first and second two output ports, first to fourth four diaphragm-type solenoid valves are mounted onto the base, the first ports of the first and second solenoid valves are respectively connected to the supply port, the second ports of the third and fourth solenoid valves are respectively connected to the discharge port, the second port of the first solenoid valve and the first port of the third solenoid valve are connected to the first output port, and the second port of the second solenoid valve and the first port of the fourth solenoid valve are connected to the second output port.
In the diaphragm-type solenoid valve of the invention, because the disc is encapsulated in the main body portion of the diaphragm and the cushion projecting portion for coming in contact with the cushion receiving portion provided to the plate in valve opening is formed behind the main body portion, impact force acting on the diaphragm in valve opening can be absorbed to protect the diaphragm. Furthermore, because the diaphragm receiving faces for preventing excessive deformation of the diaphragm when the diaphragm is pressed by operating force of the fluid are formed at faces of the valve body and the plate opposed to the main body portion, excessive deformation is generated nowhere in operation of the diaphragm and the diaphragm can be prevented to the utmost from being damaged due to fatigue or the like.
By mounting the diaphragm-type solenoid valve on a base having a flow path connected to the first and second ports to open and close the flow path, it is possible to form a complex valve having a function of a two-port valve or a three-port valve by the diaphragm-type solenoid valve and the base to obtain various flow path structures according to the flow path provided in the base.